The present invention is directed to a locknut of the type commonly used for connecting a conduit to an electrical junction box and more specifically to a locknut having a sealing ring of resilient material secured thereto to provide a sealed connection between the conduit, junction box and locknut.
Locknuts having a plurality of angular disposed teeth dispose about the circumference thereof are old and well known in the art. Such locknuts are commonly used to couple a conduit to an electrical junction box and the purpose of the angularly disposed teeth is to bite into the metal of the junction box wall when the locknut is tightened so as to scrape away any grease, paint or other foreign material which might be on the surface of the junction box wall to provide a good ground connection between the conduit and the junction box.
It is also old and well known in the art to provide a nut with a ring of sealing material on one face thereof to provide a tight connection with a wall or panel member as the nut is advanced on a threaded bolt or conduit. However, many such sealing rings protrude from the face of the nut a distance which will prevent actual contact of the nut with the wall or panel member against which the sealing ring is disposed. Such an arrangement would be completely unsatisfactory in the environment of an electrical junction box wherein most electrical codes throughout the country require that a good ground connection be formed between the wall of the junction box and the conduit through the locknut. Other sealing rings on locknuts are disposed in an annular groove in the face of the locknut spaced from the locknut threads. While such an arrangement will permit metal to metal contact between the locknut and the junction box the sealing ring will not engage the threads of the conduit nor will the sealing member extend into the gap between the threads of the conduit and the wall of the junction box to provide an air tight or water tight connection.